🔑 Key Concepts
- The surface area of a sphere is found using \(SA=4\pi r^2\).
- The radius is the distance from the center of the sphere to the outside surface.
- If the diameter is given, divide by 2 to find the radius.
- Exact answers may be written in terms of \(\pi\).
- Approximate answers can be found by using \(3.14\) for \(\pi\).
✏️ Worked Examples
🧠 Math Vocabulary
- Sphere: A three-dimensional round figure where every point on the surface is the same distance from the center.
- Radius: The distance from the center of a sphere to a point on the surface.
- Diameter: The distance across a sphere through the center. The diameter is twice the radius.
- Surface area: The total area covering the outside of a three-dimensional figure.
- In terms of \(\pi\): An exact answer that leaves \(\pi\) in the final expression instead of using a decimal approximation.
💡 Main Idea
The surface area of a sphere is found with \(SA=4\pi r^2\). Students must identify the radius, substitute it into the formula, and decide whether to leave the answer in terms of \(\pi\) or use an approximation such as \(3.14\).
📚 What You Should Already Know
Students should know how to square numbers, substitute values into formulas, multiply decimals, use units squared, and identify the difference between radius and diameter.
🚀 What Comes Next
After learning sphere surface area, students can compare exact and approximate answers, solve hemisphere surface area problems, and connect sphere formulas to volume and real-world measurement.
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